I recently had a logic board accident with my Early 2011 MBP a1286 (my bad) but was thinking of replacing it with a Mid-2012 (non-Retina) board for the CPU/GPU boost (I'm a gamer and a Mac user... figure that one out) as well as the USB 3 ports.
I found a decent deal online but for the life of me I can't find the opinions of anyone who's ever tried it. The iFixit teardowns and logic board replacement guides for both models (2011/2012) seem identical along with all of the tech specs about the wattage/voltage/etc. but the only opinion I've heard is from a repair shop guy on e-bay who says the upgrade wouldn't work (but I think he's just trying to sell me his repair services).
I'm actually amazed that there isn't more information about this kind of thing on the internet (with all the menial stuff like hacking your xbox and tricking out your iphone). For the life of me, I can't see why this 'upgrade' wouldn't work, and you guys have instilled some modicum of confidence in me so since the shop I'm buying from has a money-back guarantee I think I'm going to try it. I'll try to make a video (since there seem to be none concerning this) about it to document my failure/success.
Wish me luck!!
Edit: Placed my order for a logic board but I'm still a bit worried so I got board (hehe) and decided to see if there were any significant differences I should worry about. This is an overlay of the two boards using photos of the iFixIt teardowns (with a grain-extract filter thanks to Gimp) and there seems to be no real connection issues. Apologies for the slight distortion, I imagine the photographer was at a slightly different angle when he/she took the photos:
Ok, so after a long time waiting, I've actually ordered two separate logic boards and they both finally came on the same day.
There was a minor issue when I was re-applying the heat sinks for the USB controller and the platform controller hub (assuming the heat sinks are necessary on the 2012s). It could have been the supplier I chose or possibly these models don't heat up as much. Either way, I came up with a unique solution where I cannibal-ised my old system, popping off the screw-holders used on the old circuit board and super-gluing them to the new one in the same position. Turns out super glue is non-conductive so it was perfect solution to hold down them down so I could apply some thermal paste.
The rest of the ports, cables and screw holes lined up perfectly. Even the cables to the fan that I had broken (pulled instead of lifted). My system has officially gone from 2.3 GHz > 2.6 GHz, USB 2 > 3, bluetooth 2.1 > 4, Radeon 6750M > GeForce 650M, etc, etc. Not mentioning the previous upgrades I had done to the RAM (16GB) and the hard drive(s) [1TB Hybrid in the SuperDrive bay and a 120GB SSD in the main bay]. So YES, it is totally possible to interchange the unibody logic boards if you are so inclined. I don't think anything in my system (aside from the magsafe adapter, battery, speaker, and display) is the same as when I first purchased it.
Definitely cheaper than purchasing an altogether new system and the upgrade/repairability factor of my unibody (A1826) makes me think I'll have it around for a while longer. When I get better (I recently had jaw surgery so I can barely talk) I may even make a video about my experience as I'm surprised there aren't any on youtube already.